Lock-up clutch fuzzy logic control system of vehicle automatic transmission
First Claim
1. A system for controlling a lock-up clutch of a torque converter of an automatic transmission of a vehicle which mechanically couples a pump impeller connected to an engine output shaft with a turbine runner connected to a transmission input shaft, comprising:
- first means for determining parameters indicative of operating conditions of said vehicle at least including an engine load, a driving resistance and a current speed ratio of said torque converter between a speed of said pump impeller and a speed of said turbine runner indicting a slipping condition of said lock-up clutch;
second means for carrying out a fuzzy reasoning to determine a target speed ratio of said torque converter indicating a slipping condition of said lock-up clutch based on fuzzy production rules with each said rule having an antecedent made up of a membership function defined with respect to at least one of said parameters and a consequent made up of a membership function defined with respect to said determined target speed ration; and
third means for determining a control value of an actuator in response to said determined target speed ratio of said torque converter indicating a slipping condition of said lock-up clutch between the states in which said lock-up clutch is fully locked up and said lock-up clutch is fully not locked up including the state in which said lock-up clutch is partially locked up.
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Accused Products
Abstract
A system for controlling a lock-up clutch of a torque converter in which a target speed ratio of the torque converter of an automatic transmission of a vehicle which mechanically couples a pump impeller connected to an engine output shaft with a turbine runner connected to a transmission input shaft, is determined by carrying out a fuzzy reasoning based on fuzzy production rules using a degree of throttle opening, a grade resistance and a current speed ratio as parameters. Then a second fuzzy reasoning is carried out based on second fuzzy production rules using a deviation between the target speed ratio and the current speed ratio and the change of the deviation as parameters to determine a control value such that the lock-up clutch is controlled between a position at which the clutch is fully engaged and a position at which the clutch is fully not engaged including an intermediate position at which the clutch is partially engaged. With this system, the lock-up control can cope with various vehicle operating conditions so that the vehicle drivability and fuel consumption is improved while suppressing engine noise. This system further enables control that is better matched to the intention, decision-making, and feelings of a human driver.
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Citations
16 Claims
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1. A system for controlling a lock-up clutch of a torque converter of an automatic transmission of a vehicle which mechanically couples a pump impeller connected to an engine output shaft with a turbine runner connected to a transmission input shaft, comprising:
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first means for determining parameters indicative of operating conditions of said vehicle at least including an engine load, a driving resistance and a current speed ratio of said torque converter between a speed of said pump impeller and a speed of said turbine runner indicting a slipping condition of said lock-up clutch; second means for carrying out a fuzzy reasoning to determine a target speed ratio of said torque converter indicating a slipping condition of said lock-up clutch based on fuzzy production rules with each said rule having an antecedent made up of a membership function defined with respect to at least one of said parameters and a consequent made up of a membership function defined with respect to said determined target speed ration; and third means for determining a control value of an actuator in response to said determined target speed ratio of said torque converter indicating a slipping condition of said lock-up clutch between the states in which said lock-up clutch is fully locked up and said lock-up clutch is fully not locked up including the state in which said lock-up clutch is partially locked up. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for controlling a lock-up clutch of a torque converter of an automatic transmission of a vehicle which mechanically couples a pump impeller connected to an engine output shaft with a turbine runner connected to a transmission input shaft, comprising:
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first means for determining parameters indicative of operating conditions of said vehicle at least including an engine load, a driving resistance and a speed ratio of said torque converter; second means for carrying out a fuzzy reasoning to determine a target speed ratio based on fuzzy production rules with each said rule having an antecedent made up of a membership function defined with respect to at least one of said parameters and a consequent made up of a membership function defined with respect to said determined target speed ration;
wherein said fuzzy production rules include at least one rule which is given a priority over the others and;third means for determining a control value of an actuator in response to said determined target speed ratio between the states in which said lock-up clutch is fully locked up and said lock-up clutch is fully not locked up including the state in which said lock-up clutch is partially locked up. - View Dependent Claims (15)
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16. A system for controlling a lock-up clutch of a torque converter of an automatic transmission of a vehicle which mechanically couples a pump impeller connected to an engine output shaft with a turbine runner connected to a transmission input shaft, comprising:
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first means for determining parameters indicative of operating conditions of said vehicle at least including an engine load, a driving resistance and a current speed ratio of said torque converter between a speed of said pump impeller and a speed of said turbine runner indicating a slipping condition of said lock-up clutch; second means for carrying out a fuzzy reasoning to determine a target speed ratio of said torque converter indicating a slipping of said lock-up clutch; and third means for determining a control value of an actuator in response to said determined target speed ratio between the states in which said lock-up clutch is fully locked up and said lock-up clutch is fully not locked up including the state in which said lock-up clutch is partially locked up.
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Specification